CLOSE to tears, an "upset" and "agitated" Garry Reginald 'Shorty' Dubois made a jailhouse confession in which he feared being extradited to Joh Bjelke-Petersen's Queensland where he faced life behind bars for an alleged triple murder - or death at the hands of his associate Vincent O'Dempsey.

Mr Dubois and Mr O'Dempsey are accused of the murder of 34-year-old Barbara McCulkin and the rape and murder of her daughters Vicki, 13, and 11-year-old Leanne 42 years ago.

The Highgate Hill family disappeared from their home on January 16, 1974.

Mr Dubois, from Torbanlea, has pleaded not guilty in Brisbane Supreme Court to one charge of deprivation of liberty, two of rape and three charges of murder.

Mr O'Dempsey, a 78-year-old Warwick resident, is scheduled to face trial next year.

Former South Australian police officers John Attwood and James Munro had the job of arresting Mr Dubois and ensuring he appeared in Adelaide Magistrates Court for a July 1980 extradition hearing on drugs and failing to appear in court charges.

Mr Dubois became increasingly stressed while waiting in the holding cells not long before he was due to face the magistrate 36 years ago.

When asked if he knew anything about the alleged murders, Mr Dubois told the officers: "I don't know anything about it."

"You know me, I don't talk.

"Come on, you know me better than that."

The court has heard that the McCulkins may have had some knowledge of the Whiskey Au Go Go nightclub blaze that killed 15 people in 1973.

Crown prosecutor David Meredith told the court last week that Garry Dubois, Mr O'Dempsey and three other men were behind the torching of the Torino nightclub about 10 days before the Whiskey Au Go Go went up in flames.

The accused feared their involvement in the Torino blaze could see them linked to the Whiskey fire.

On Monday Garry Dubois's brother Paul claimed that during a phone conversation, Garry Dubois said: "Barbara McCulkin had information on O'Dempsey that he felt could've got him 20 years and this is how he dealt with it".

Mr Meredith has said the prosecution's case is not that Mrs McCulkin was blackmailing O'Dempsey.

However, he said her knowledge of the two fires may have been a motive for her death.

The McCulkins' bodies have not been found.

The trial continues before Justice Peter Applegarth.

Witness drinking with friend who made 'murder' revelation

A NEW South Wales man claims he was told who killed the McCulkin family in 1974.

Douglas Meredith told a Brisbane Supreme Court on Wednesday that a man called Tommy Hamilton told him Vincent O'Dempsey murdered 34-year-old Barbara and her daughters.